N-Halamine-coated cotton for antimicrobial and detoxification applications Xuehong Ren a , Akin Akdag a , Hasan B. Kocer b , S.D. Worley a, * , R.M. Broughton b , T.S. Huang c a Department of Chemistry and Biochemistry, Auburn University, 258 Chemistry Building, Auburn, Alabama 36849, USA b Department of Polymer and Fiber Engineering, Auburn University, Auburn, Alabama 36849, USA c Department of Nutrition and Food Science, Auburn University, Auburn, Alabama 36849, USA article info Article history: Received 15 January 2009 Received in revised form 25 February 2009 Accepted 23 March 2009 Available online 28 March 2009 Keywords: Biocidal Cellulose Bacteria Antimicrobial N-Halamine abstract A new N-halamine precursor, 3-(2,3-dihydroxypropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane- 2,4-dione (TTDD diol), was synthesized and bonded onto cotton fabrics. Fabrics with variable amounts of chlorine loading were prepared by using several concentrations of TTDD diol. A second N-halamine precur- sor, 3-(3-triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione (TTDD silox- ane), was also synthesized and bound to cotton for comparison purposes. The coated cotton fabrics contained two types of N–Cl moieties after chlorination of the amine and amide groups. Swatches with var- iable chlorine loadings were challenged with Staphylococcus aureus and Escherichia coli O157:H7 as a func- tion of contact time. The biocidal test results showed that the chlorine loadings and surface hydrophobicities influenced the antimicrobial efficacies. The chlorinated swatches have also been employed to oxidize the simulant of chemical mustard to the less toxic sulfoxide derivative. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Antimicrobial organic materials comprised of quaternary ammonium salts (Klibanov, 2007; Kurt, Gamble, & Wynne, 2008; Kurt, Wood, Ohman, & Wynne, 2007; Lewis & Klibanov, 2006; Murata, Koepsel, Matyjaszewski, & Russell, 2007; Park, Wang, & Klibanov, 2006; Sauvet, Fortuniak, Kazmierski, & Chojnowski, 2003; Waschinski & Tiller, 2005; Waschinski et al., 2008a, 2008b; Waschinski, Herdes, Schueler, & Tiller, 2005), phosphonium salts (Kenawy & Mahmoud, 2003; Kenawy, Abdel-Hay, El-Magd, & Mah- moud, 2006; Kenawy, Abdel-Hay, El-Shanshoury, & El-Newehy, 2002), and N-halamine compounds (Barnes et al., 2006; Chen et al., 2004a, 2004b, 2003a, 2003b; Chen & Sun, 2006; Grunzinger et al., 2007; Kocer et al., 2008; Kou et al., 2006; Lee, Broughton, Ak- dag, Worley, & Huang, 2008; Liang et al., 2007a, 2007b, 2006; Liu & Sun, 2008; Luo & Sun, 2006, 2008; Luo, Chen, & Sun, 2006; Makal, Wood, Ohman, & Wynne, 2006; Ren, Kocer, Worley, Broughton, & Huang, 2009; Ren et al., 2008a, 2008b; Sun & Xu, 1999a, 1999b, 1999c; Sun & Sun, 2001, 2002) have been used as antimicrobial agents in infection control. Among these, N-halamine materials have been extensively studied due to their stabilities, regenerabil- ities, and efficacies in inactivating bacteria. The infection of hospi- tal personnel and patients with pathogenic microorganisms could be minimized if they were equipped with protective clothing con- taining these materials. Cotton is an ideal medium for the growth of bacteria because of its composition. On the other hand, cotton can be easily modified to produce antimicrobial cellulose. Sun and coworkers have suc- cessfully employed wet finishing or grafting techniques to produce durable and regenerable antibacterial cotton fabrics (Liu & Sun, 2008; Sun & Xu, 1999a; Sun & Xu, 1999b; Sun & Xu, 1999c; Sun & Sun, 2001; Sun & Sun, 2002). Recently, a series of N-halamine siloxanes were synthesized and coated onto cotton to produce antimicrobial cellulose in these laboratories (Barnes et al., 2006; Kocer et al., 2008; Liang et al., 2007a; Liang et al., 2006; Liang et al., 2007b; Ren et al., 2008b). N-Halamine materials function as biocides through the direct contact of microbial cells with oxida- tive halogen. The hydrophobicities of N-halamine precursors and the increasing hydrophobicities of their halogenated derivatives influence the surface contact of the biocides and the cells, and in turn, may lower the rate of disinfection. On the other hand, an in- crease of oxidative N–X moieties provides more contact sites and can increase the disinfection rate. The work of Chen and Sun showed that an increase in alkyl chain length at the 3 position of the hydantoin ring can cause less contact sites with the cells and a lower rate of disinfection due to the increase of hydrophobicity on the surfaces of the antimicrobial materials. Kocer et al. have studied the effect of alkyl substitution at the 5 position of the hydantoin ring of N-halamine siloxanes on the rate of inactivation of microbes and reached the conclusion that hydrophobicity is one of the major factors that influence the disinfection rate. However, the N-halamine siloxanes reported above are only partially soluble in water and need the assistance of organic solvents for dissolution which can be a liability for industrial applications. 0144-8617/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbpol.2009.03.029 * Corresponding author. Tel.: +1 334 844 6980; fax: +1 334 844 6959. E-mail address: worlesd@auburn.edu (S.D. Worley). Carbohydrate Polymers 78 (2009) 220–226 Contents lists available at ScienceDirect Carbohydrate Polymers journal homepage: www.elsevier.com/locate/carbpol